In Subspace Radio #33, Rob and I are surprisingly okay with “Tomorrow and Tomorrow and Tomorrow”'s revelations about where exactly in the timeline certain ill-fated experiments took place. In celebration, we explore two other significant rewritings, or retrospective continuity changes (retcons) that Star Trek has indulged in in the past, including “Affliction” and “Divergence” (ENT), and “The Host” (TNG).